Diagnostic and recirculation control systems and methods

ABSTRACT

A vehicle system includes: a heating, ventilation, and air conditioning (HVAC) system including: a passenger cabin air filter; and a blower configured to draw air through the passenger cabin air filter and blow air into a passenger cabin of a vehicle; an olfaction sensor configured to measure an amount of a chemical in air in a duct of the HVAC system downstream of the passenger cabin air filter; and a filter module configured to determine and indicate whether to replace the passenger cabin air filter based on the amount of the chemical in the air measured by the olfaction sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/067,912, filed on Aug. 20, 2020. The entire disclosure of the application referenced above is incorporated herein by reference.

FIELD

The present disclosure relates to vehicles and more particularly to systems and methods for controlling recirculation of a heating, ventilation, and air conditioning (HVAC) system of a vehicle and diagnosing a need for replacement of a cabin air filter of the HVAC system.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Vehicles have been recalled due to carbon monoxide entering their passenger cabins and for other reasons. Humans may be overcome by carbon monoxide and lose consciousness.

There may be numerous other situations where chemicals could be present within a passenger cabin of a vehicle. For example, a user may bring an aerosol can in to the passenger cabin of a vehicle and forget to take it out. Due to heat or cold, the aerosol can could emit its contents into the passenger cabin. One or more users could enter the vehicle later and breathe the contents without knowledge.

Electric vehicles include one or more batteries that contain chemicals, such as lithium. The batteries may be located under the passenger cabin and, under some circumstances, can rupture and emit chemicals. Some chemicals that may be present within a passenger cabin of a vehicle may be odorless and colorless.

SUMMARY

In a feature, a vehicle system includes: a heating, ventilation, and air conditioning (HVAC) system including: a passenger cabin air filter; and a blower configured to draw air through the passenger cabin air filter and blow air into a passenger cabin of a vehicle; an olfaction sensor configured to measure an amount of a chemical in air in a duct of the HVAC system downstream of the passenger cabin air filter; and a filter module configured to determine and indicate whether to replace the passenger cabin air filter based on the amount of the chemical in the air measured by the olfaction sensor.

In further features, the chemical is volatile organic compounds (VOCs).

In further features, the chemical is particulate matter.

In further features, the chemical is carbon monoxide.

In further features, the filter module is configured to indicate to replace the passenger cabin air filter when the amount of the chemical in the air measured by the olfaction sensor is greater than a predetermined amount.

In further features, the filter module is configured to indicate that replacement of the passenger cabin air filter is not needed when the amount of the chemical in the air measured by the olfaction sensor is less than the predetermined amount.

In further features, a second olfaction sensor is configured to measure a second amount of the chemical in air in the duct of the HVAC system upstream of the passenger cabin air filter, where the filter module is configured to determine and indicate whether to replace the passenger cabin air filter further based on the second amount of the chemical in the air measured by the olfaction sensor.

In further features, the filter module is configured to indicate whether to replace the passenger cabin air filter based on a difference between the amount and the second amount is greater than a predetermined amount.

In further features, the filter module is configured to indicate to replace the passenger cabin air filter when at least one of: the difference is greater than a predetermined amount; and a magnitude of the difference is greater than the predetermined amount.

In further features, an alert module is configured to illuminate a visual indicator to replace the passenger cabin air filter in response to an indication by the filter module configured to replace the passenger cabin air filter.

In further features, an alert module is configured to output an audible indicator to replace the passenger cabin air filter via at least one speaker in response to an indication by the filter module configured to replace the passenger cabin air filter.

In further features, a communication module is configured to wirelessly transmit an indicator to replace the passenger cabin air filter to a remote device via an antenna in response to an indication by the filter module configured to replace the passenger cabin air filter.

In a feature, a vehicle system includes: a heating, ventilation, and air conditioning (HVAC) system including: a passenger cabin air filter; a blower; and a recirculation door configured to: when in a first position, allow the blower to draw air from outside of the passenger cabin through the passenger cabin air filter; and when in a second position: block airflow through the passenger cabin air filter to the blower; and allow the blower to air from within the passenger cabin to the blower; an olfaction sensor configured to measure an amount of a chemical in air upstream of the passenger cabin air filter; and a recirculation module configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount.

In further features, the chemical is volatile organic compounds (VOCs).

In further features, the chemical is particulate matter.

In further features, the chemical is carbon monoxide.

In further features, the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than the predetermined amount without receiving user input indicative of a request to actuate the recirculation door to the second position.

In further features, the recirculation module is further configured to actuate the recirculation door to the second position in response to receipt of user input indicative of a request to actuate the recirculation door to the second position.

In further features, the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount during operation of the HVAC system in a heating mode.

In further features, the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount during operation of the HVAC system in a cooling mode.

Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a functional block diagram of an example vehicle system.

FIG. 2 is a diagram of an example heating, ventilation, and air conditioning (HVAC) system of a vehicle.

FIG. 3 is a functional block diagram of an example control system.

FIG. 4 is a flowchart depicting an example method of indicating whether a cabin air filter should be replaced.

FIG. 5 is a flowchart depicting an example method of automatically initiating recirculation mode operation.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

A blower of a heating, ventilation, and air conditioning (HVAC) system of a vehicle may operate draw fresh air through a passenger cabin air filter when a recirculation door is in a first position. When the recirculation door is in a second position, the blower may draw air from within the passenger cabin.

The passenger cabin air filter filters one or more chemicals (e.g., carbon monoxide, particulate, and/or volatile organic compounds (VOCs)) from air before the air is blown into the passenger cabin. Over time, however, the passenger cabin air filter may become less effective at filtering the chemical(s) from the air.

The present application involves control systems and methods for determining and indicating whether to replace the passenger cabin air filter. A control module indicates whether to replace the passenger cabin air filter based on measurements from an olfaction sensor located downstream of the passenger cabin air filter. The control module may indicate whether to replace the passenger cabin air filter further based on measurements from an olfaction sensor located upstream of the passenger cabin air filter.

The recirculation door may be actuated to the second position in response to receipt of user input indicative of a request to operate in the circulation mode. The present application involves selectively automatically actuating the recirculation door to the second position (without receiving the user input) based on one or more measurements from the olfaction sensor located upstream of the passenger cabin air filter. This may prevent outside air having a high amount of one or more chemicals from being drawn into the passenger cabin.

FIG. 1 includes a functional block diagram including an example vehicle 5. The vehicle 5 includes a control module 8 and one or more olfaction sensors, such as olfaction sensor 10. Examples of olfaction sensors in vehicles include, for example, particulate matter sensors, carbon monoxide (or other carbon oxide) sensors, volatile organic compound (VOC) sensors, and other types of sensors. The vehicle 5 may include one or more different types of olfaction sensors.

The olfaction sensor(s) are each configured to measure an amount of one or more chemicals within a passenger cabin of the vehicle 5. For example, the vehicle 5 may include a particulate matter sensor configured to measure one or more amounts (e.g., concentrations or mass flow rates) of particulate of one or more different sizes in air within the passenger cabin. Additionally or alternatively, the vehicle 5 may include a carbon monoxide sensor configured to measure an amount (e.g., concentration) of carbon monoxide in air within the passenger cabin. Additionally or alternatively, the vehicle 5 may include a VOC sensor configured to measure an amount (e.g., concentration) of VOCs within the passenger cabin.

The control module 8 may receive the measurements from the olfaction sensor(s) and take one or more remedial actions based on the measurements. For example, when one or more amount of one or more chemicals (e.g., particulate, carbon monoxide, VOCs) measured by one or more olfaction sensors is/are greater than one or more respective predetermined amount/s (e.g., of particulate matter, carbon monoxide, or VOCs, respectively), the control module 8 may take one or more remedial actions. The predetermined amount/s is/are greater than zero.

For example, the control module 8 may open one or more windows 12 of the vehicle 5 when the amount of a chemical is greater than the predetermined amount. Additionally or alternatively, the control module 8 may generate an alert within the vehicle 5 when the amount of a chemical is greater than the predetermined amount. For example, the control module 8 may generate or display a visual alert, such as via a visual indicator 14 that is visible within the passenger cabin of the vehicle 5. The visual indicator 14 may be, for example, one or more indicator lights, a display, or another suitable type of visual indicator. Additionally or alternatively, the control module 8 may output an audible alert, such as via one or more speakers. Additionally or alternatively, the control module 8 may output a tactile alert, such as via turning on one or more vibrating devices, such as located in one or more seats, in a steering wheel, or in another suitable location.

Additionally or alternatively, the control module 8 may turn on a heating ventilation and air conditioning (HVAC) system 16 of the vehicle 5 when the amount of a chemical is greater than the predetermined amount. The control module 8 may, for example, turn on a blower of the HVAC system 16 and control one or more actuators of the HVAC system 16 to recirculate air from within the passenger cabin to outside of the passenger cabin. This is discussed in more detail below.

Additionally or alternatively, the control module 8 may store an indicator in memory of the vehicle when the amount of a chemical is greater than the predetermined amount. The indicator may indicate that the amount of the chemical was greater than the predetermined amount. The control module 8 may also store a time stamp (e.g., including a date and a time of the occurrence) with the indicator.

Additionally or alternatively, the control module 8 may transmit an indicator to a remote device 20, such as of a fleet operator, when the amount of a chemical is greater than the predetermined amount. The control module 8 may transmit the indicator via one or more communication networks, such as a cellular communication network, a satellite communication network, a Wi-Fi communication network, or another suitable type of communication network.

FIG. 2 is a diagram of an example HVAC system of the vehicle 5.

The HVAC system includes one or more duct openings 104 through which a blower 208 can blow air into the passenger cabin of the vehicle. One or more doors 112 (e.g., mode doors) may actuate to open and close ones of the duct openings 104. A blend door 116 may actuate and control whether the air from the blower 208 flows past/through a heater core 120 before flowing into the passenger cabin. When warm coolant is flowing through the heater core 120, the heater core 120 warms air flowing through/past the heater core 120. The coolant may be warmed, for example, by an internal combustion engine of the vehicle.

The air also flows past/through an evaporator core 124 before flowing into the passenger cabin. When an air conditioning compressor (not shown) is pumping refrigerant through the evaporator core 124, the evaporator core 124 cools air flowing through/past the evaporator core 124. A drain 128 may be implemented downstream of the evaporator core 124 and allow condensation (e.g., from the evaporator core 124) to drain from the HVAC system.

The blower 208 operates (e.g., rotates) and blows air into the passenger cabin. The blower 208 operates when power (e.g., a direct current (DC) voltage or an alternating current (AC) voltage) is applied to (an electric motor of) the blower 208 by the control module 8.

A recirculation door (or flap) 136 actuates and controls whether the blower 208: (a) draws fresh air in from outside of the passenger cabin through a filter 144 via a first inlet 140; or (b) draws air from within the passenger cabin via a second inlet 148. The control module 8 actuates the recirculation door 136 to a first state/position 160 to (b) draw air frim within the passenger cabin via the second inlet 148. The control module 8 actuates the recirculation door 136 to a second state/position 164 to (a) draw fresh air in from outside of the passenger cabin through the filter 144 and the first inlet 140. When (b) drawing air from within the passenger cabin via the second inlet 148, the HVAC system may be said to be operating in a recirculation mode because air from within the passenger cabin is being recirculated back to the passenger cabin.

An olfaction sensor 200-A may be implemented upstream of the filter 144 and/or an olfaction sensor 200-B may be implemented downstream of the filter 144. The olfaction sensors 200-A and 200-B may collectively be referred to as olfaction sensors 200. While both of the olfaction sensors 200-A and 200-B are shown, one of the olfaction sensors 200 may be omitted in some implementations.

Examples of olfaction sensors include, for example, particulate matter sensors, carbon monoxide (or other carbon oxide) sensors, VOC sensors, and/or other types of sensors. The olfaction sensor 200 are each configured to measure an amount of one or more chemicals at their locations. For example, the olfaction sensors 200 may include a particulate matter sensor configured to measure one or more amounts (e.g., concentrations or mass flow rates) of particulate of one or more different sizes in air at their locations. Additionally or alternatively, the olfaction sensors 200 may include a carbon monoxide sensor configured to measure an amount (e.g., concentration) of carbon monoxide in air at their locations. Additionally or alternatively, the olfaction sensors 200 may include a VOC sensor configured to measure an amount (e.g., concentration) of VOCs within the passenger cabin.

The control module 8 receives the measurements from the olfaction sensors 200 and may take one or more remedial actions based on the measurements.

For example, the control module 8 may determine and indicate whether the filter 144 should be replaced based on the measurements of the olfaction sensor 200-B (downstream of the filter 144). The control module 8 may indicate that the filter 144 should be replaced when one or more measurements of the olfaction sensor 200-B are greater than a predetermined amount. The measurement(s) exceeding the predetermined amount may indicate that the filter 144 is full/dirty and should be replaced. The control module 8 may indicate that the filter 144 does not yet need to be replaced when the measurement(s) of the olfaction sensor 200-B are less than the predetermined amount(s).

In various implementations, the control module 8 may determine whether the filter 144 should be replaced based on the measurements from the olfaction sensor 200-A and the olfaction sensor 200-B. For example, the control module 8 may determine that the filter 144 should be replaced when a difference in particulate matter measured by the olfaction sensors 200-A and 200-B is greater than a predetermined amount. This may indicate that the filter 144 is insufficiently filtering particulate matter. The control module 8 may determine (and indicate) that the filter 144 need not yet be replaced when the difference in particulate matter is less than the predetermined amount.

The control module 8 may generate or display a visual alert, such as via the visual indicator 14 that is visible within the passenger cabin of the vehicle 5, when the control module 8 determines that the filter 144 should be replaced. Additionally or alternatively, the control module 8 may output an audible alert, such as via one or more speakers, when the control module 8 determines that the filter 144 should be replaced. Additionally or alternatively, the control module 8 may output a tactile alert, such as via turning on one or more vibrating devices, such as located in one or more seats, in a steering wheel, or in another suitable location, when the control module 8 determines that the filter 144 should be replaced.

By implementing the olfaction sensor 200-B downstream of the filter 144, the control module 8 can detect the presence of mildew/VOC/particulate flowing into the passenger cabin and indicate (e.g., to the driver or owner) that the filter 144 should be replaced.

The control module 8 may automatically initiate (or switch to) the recirculation mode (e.g., from drawing in air through the filter 144) based on the measurements from the olfaction sensor 200-A (upstream of the filter 144). In other words, the control module 8 may determine whether to operate the HVAC system in the recirculation mode (independently of user input to operate in the recirculation mode) based on the measurements from the olfaction sensor 200-A.

The control module 8 may perform or switch to the recirculation mode (including actuating the recirculation door 136 to the first position 160, such as from the second state 164, and turning on or maintaining on the blower 208) when one or more of the measurements (e.g., particulate, VOCs) from the olfaction sensor 200-A is greater than a respective predetermined amount. The control module 8 may not automatically perform the recirculation mode when the measurements (e.g., VOCs and particulate matter) from the olfaction sensor 200-A are less than the respective predetermined amounts. The predetermined amounts are greater than zero and may be calibrated based on poor fresh air quality.

The control module 8 may switch to or perform the recirculation mode when one or more of the measurements (e.g., VOCs, particulate) of the olfaction sensor 200-A are greater than the respective predetermined amount to prevent poor quality fresh air from being blown into the passenger cabin. Instead, cooling or heating can continue by cooling or heating air from within the passenger cabin before recirculating the cooled or heated air back into the passenger cabin.

By implanting the olfaction sensor 200-A upstream of the filter 144, when high VOC and/or particulate matter is detected, the control module 8 can automatically switch to or initiate recirculation mode to limit the amount of outside air blown into the passenger cabin.

While an example location of the olfaction sensor 200-A is provided, the olfaction sensor 200-A may be implemented in another suitable location upstream of the filter 144. While an example location of the olfaction sensor 200-B is provided, the olfaction sensor 200B may be implemented in another suitable location downstream of the filter 144.

FIG. 3 is a functional block diagram of an example control system. The olfaction sensor 10 may make measurements of air within the passenger cabin and may be a VOC sensor, a particulate matter sensor, or a carbon monoxide sensor. In various implementations, the olfaction sensor 10 may include two or more of a VOC sensor, a particulate matter sensor, and a carbon monoxide sensor.

A comparison module 504 compares a measurement from the olfaction sensor 10 with a predetermined value and generates an output signal based on the comparison. The measurement may be, for example, an amount of particulate, an amount of VOCs, or an amount of carbon monoxide. The comparison module 504 may set the output signal to the first state when the measurement is less than the predetermined value and set the output signal to a second state when the measurement is greater than or equal to the predetermined value.

The comparison module 504 may obtain the predetermined value from memory 508. The predetermined value may be a fixed predetermined value that is greater than zero. Alternatively, the predetermined value may be variable.

One or more remedial actions may be taken when the output signal of the comparison module 504 is in the second state. For example, a window actuator module 516 controls actuation (opening and closing) of one or more window actuators, such as window actuator 520, of the vehicle. The window actuator 520 opens (e.g., lowers) and closes (e.g., raises) a window of the vehicle. The window actuator module 516 may control one or more window actuators to open one, more than one, or all of the windows of the vehicle when the output signal of the comparison module 504 is in the second state. Opening the window(s) may include, for example, opening the window(s) to a partially open position further than the window(s) is/are presently open or opening the window(s) to a fully open position.

Additionally or alternatively, an alert module 524 may generate an alert (e.g., visually the visual indicator 14, audibly via one or more speakers, and/or haptically via one or more vibrating devices) when the output signal of the comparison module 504 is in the second state. Additionally or alternatively, a communication module 540 may wirelessly transmit an indicator to the remote device 20 via one or more antennas 544 when the output signal of the comparison module 504 is in the second state. Additionally or alternatively, a storage module 548 may store an indicator in the memory 508 when the output signal of the comparison module 504 is in the second state. The indicator may indicate that the amount of the chemical was greater than the predetermined value. The storage module 548 may also store a time stamp (e.g., including a date and a time of the occurrence) with the indicator. A clock 552 may track the date and time.

A blower control module 528 controls operation of the blower 208, such as whether the blower 208 is ON or OFF. The blower control module 528 may also control a speed of the blower 208. A door actuator module 536 actuates the recirculation door 136 and other doors 538 of the HVAC system, such as the doors 112 and the blend door 116.

A filter module 556 may determine whether the filter 144 should be replaced/changed (with a new filter) based on the measurement from the olfaction sensor 200-B or based on the measurements from both the olfaction sensor 200-A and 200-B. For example, the filter module 556 may determine that the filter 114 should be replaced when one or more measurements of the olfaction sensor 200-B are greater than a predetermined value/amount. The measurement(s) exceeding the predetermined amount may indicate that the filter 144 is full/dirty (or otherwise deficient at filtering the chemical) and should be replaced. The filter module 556 may indicate that the filter 144 does not yet need to be replaced when the measurement(s) of the olfaction sensor 200-B are less than the predetermined value/amount(s).

Additionally or alternatively, the filter module 556 may determine whether the filter 144 should be replaced based on the measurements from both the olfaction sensor 200-A and the olfaction sensor 200-B. For example, the filter module 556 may determine that the filter 144 should be replaced when a difference (e.g., a magnitude of the difference) in the measurements (e.g., particulate matter, VOCs, or carbon monoxide) measured by the olfaction sensors 200-A and 200-B is greater than a predetermined amount. This may indicate that the filter 144 is insufficiently filtering the chemical (e.g., particulate matter, VOCs, or carbon monoxide). The filter module 556 may determine that the filter 144 need not yet be replaced when the difference in the measurements is less than the predetermined amount.

The filter module 556 may set the difference, for example, based on or equal to the measurement of the olfaction sensor 200-A minus the measurement of the olfaction sensor 200-B. The measurement of the olfaction sensor 200-B should be less than the measurement of the olfaction sensor 200-A if the filter 144 is properly filtering the chemical from air. In various implementations, a magnitude of the difference may be used.

The filter module 556 may indicate whether the filter 144 should be replaced via a filter replace signal. The filter module 556 may set the filter replace signal to a first state when the filter 144 need not yet be replaced. The filter module 556 may set the filter replace signal to a second state when the filter 144 should be replaced.

The alert module 524 may generate a visual alert, such as via the visual indicator 14 that is visible within the passenger cabin of the vehicle 5, when the filter replace signal is in the second state. Additionally or alternatively, the alert module 524 may generate an audible alert, such as via one or more speakers, when the filter replace signal is in the second state. Additionally or alternatively, the alert module 524 may generate a tactile alert, such as via turning on one or more vibrating devices, such as located in one or more seats, in a steering wheel, or in another suitable location, when the filter replace signal is in the second state. Additionally or alternatively, the communication module 540 may transmit an indicator (that the filter 144 should be replaced) to the remote device 20 when the filter replace signal is in the second state.

By implementing the olfaction sensor 200-B downstream of the filter 144, the control module 8 can detect the presence of mildew/VOC/particulate flowing into the passenger cabin and indicate (e.g., to the driver or owner) that the filter 144 should be replaced.

A recirculation module 560 selectively triggers the door actuator module 536 to actuate the recirculation door 136 to the first position 160 to operate the HVAC system in the recirculation mode. For example, the recirculation module 560 triggers the door actuator module 536 to actuate (or maintain) the recirculation door 136 to the first position 160 in response to receipt of user input indicative of a request to operate in the recirculation mode from a user input device 564. The user input device 564 may be, for example, a button, or a switch. In various implementations, the user input device 564 may include a touchscreen display, such as a touchscreen display of an infotainment system of the vehicle.

Additionally, the recirculation module 560 may automatically trigger the door actuator module 536 to actuate the recirculation door 136 to the first position 160 to operate the HVAC system in the recirculation mode (without receiving user input to operate in the recirculation mode) based on one or more of the measurements from the olfaction sensor 200-A. For example, the recirculation module 560 may (without receiving user input to operate in the recirculation mode) trigger the door actuator module 536 to actuate the recirculation door 136 to the first position 160 to operate the HVAC system in the recirculation mode when one or more measurements from the olfaction sensor 200-A are greater than a predetermined amount/value. The predetermined amount/value may be stored in the memory 508 and is greater than zero. In various implementations, the predetermined amount/value may be variable. The predetermined amount/value may be different than the predetermined value used by the comparison module 504. The measurement(s) being greater than the predetermined amount/value may indicate that the air outside of the vehicle includes a high amount of the chemical such that outside air should not be brought into the passenger cabin.

FIG. 4 is a flowchart depicting an example method of selectively indicating whether the filter 144 should be replaced. Control begins with 604 where the filter module 556 receives a measurement from the olfaction sensor 200-B. The filter module 556 may also receive a measurement from the olfaction sensor 200-A. The olfaction sensors 200-A and 200-B include the same type of sensor such that the measurements are of the same chemical (e.g., particulate matter, carbon monoxide, or VOCs).

At 608, the filter module 556 determines whether the filter 144 should be replaced, as discussed above. For example, the filter module 556 may determine that the filter 144 should be replaced when one or more measurements from the olfaction sensor 200-B is/are greater than the predetermined value/amount. Additionally or alternatively, the filter module 556 may determine that the filter 144 should be replaced when a difference (e.g., a magnitude of the difference) in the measurements (e.g., particulate matter, VOCs, or carbon monoxide) measured by the olfaction sensors 200-A and 200-B is greater than the predetermined amount. If 608 is false, the filter module 556 sets the filter replace signal to the first state, and the alert module 524 does not generate an alert to replace the filter 144 at 612. If 608 is true, the filter module 556 sets the filter replace signal to the second state, and the alert module 524 generates one or more alerts (e.g., visually, audibly, haptically, etc.) to replace the filter 144 at 616. While the example of FIG. 4 is shown as ending, control may return to 604.

FIG. 5 is a flowchart depicting an example method of automatically initiating recirculation mode operation. Control begins with 704, where the recirculation module 560 determines whether the blower 208 is ON. If 704 is true, control continues with 708. If 704 is false, control may end.

At 708, the recirculation module 560 receives the measurement from the olfaction sensor 200-A disposed upstream of the filter 144. At 712, the recirculation module 560 may determine whether the measurement is less than the predetermined value. If 712 is true, the recirculation module 560 maintains the current position of the recirculation door 136 at 716, and control may end. If 712 is false, the recirculation module 560 may automatically (without receiving a request via the user input device 564 to operate in the recirculation mode) actuate the recirculation door 136 (via the door actuator module 536) to the first position 160 at 720. This prevents the air from outside of the cabin (with a high measured amount of a chemical) from being drawn into the passenger cabin via the blower 208. While the example of FIG. 5 is shown as ending, control may return to 704.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

In this application, including the definitions below, the terms “module” and “system” may refer to, be part of, or include circuits or circuitry that may include processor hardware (shared, dedicated, or group) that executes code and memory hardware (shared, dedicated, or group) that stores code executed by the processor hardware. The code is configured to provide the features of the modules and systems described herein. In addition, in this application the terms “module” and “system” may be replaced with the term “circuit.” The term “memory hardware” may be a subset of the term computer-readable medium. The term computer-readable medium does not encompass transitory electrical and electromagnetic signals propagating through a medium, and may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory tangible computer readable medium include nonvolatile memory, volatile memory, magnetic storage, and optical storage.

The apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs. The functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.

The computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium. The computer programs may also include or rely on stored data. The computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

The computer programs may include: (i) descriptive text to be parsed, such as JavaScript Object Notation (JSON), hypertext markup language (HTML) or extensible markup language (XML); (ii) assembly code; (iii) object code generated from source code by a compiler; (iv) source code for execution by an interpreter; (v) source code for compilation and execution by a just-in-time compiler, etc. As examples only, source code may be written using syntax from languages including C, C++, C#, Objective C, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5, Ada, ASP (active server pages), PHP, Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, and Python®.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 

What is claimed is:
 1. A vehicle system, comprising: a heating, ventilation, and air conditioning (HVAC) system including: a passenger cabin air filter; and a blower configured to draw air through the passenger cabin air filter and blow air into a passenger cabin of a vehicle; an olfaction sensor configured to measure an amount of a chemical in air in a duct of the HVAC system downstream of the passenger cabin air filter; and a filter module configured to determine and indicate whether to replace the passenger cabin air filter based on the amount of the chemical in the air measured by the olfaction sensor.
 2. The vehicle system of claim 1 wherein the chemical is volatile organic compounds (VOCs).
 3. The vehicle system of claim 1 wherein the chemical is particulate matter.
 4. The vehicle system of claim 1 wherein the chemical is carbon monoxide.
 5. The vehicle system of claim 1 wherein the filter module is configured to indicate to replace the passenger cabin air filter when the amount of the chemical in the air measured by the olfaction sensor is greater than a predetermined amount.
 6. The vehicle system of claim 5 wherein the filter module is configured to indicate that replacement of the passenger cabin air filter is not needed when the amount of the chemical in the air measured by the olfaction sensor is less than the predetermined amount.
 7. The vehicle system of claim 1 further comprising a second olfaction sensor configured to measure a second amount of the chemical in air in the duct of the HVAC system upstream of the passenger cabin air filter, wherein the filter module is configured to determine and indicate whether to replace the passenger cabin air filter further based on the second amount of the chemical in the air measured by the olfaction sensor.
 8. The vehicle system of claim 7 wherein the filter module is configured to indicate whether to replace the passenger cabin air filter based on a difference between the amount and the second amount is greater than a predetermined amount.
 9. The vehicle system of claim 8 wherein the filter module is configured to indicate to replace the passenger cabin air filter when at least one of: the difference is greater than a predetermined amount; and a magnitude of the difference is greater than the predetermined amount.
 10. The vehicle system of claim 1 further comprising an alert module configured to illuminate a visual indicator to replace the passenger cabin air filter in response to an indication by the filter module configured to replace the passenger cabin air filter.
 11. The vehicle system of claim 1 further comprising an alert module configured to output an audible indicator to replace the passenger cabin air filter via at least one speaker in response to an indication by the filter module configured to replace the passenger cabin air filter.
 12. The vehicle system of claim 1 further comprising a communication module configured to wirelessly transmit an indicator to replace the passenger cabin air filter to a remote device via an antenna in response to an indication by the filter module configured to replace the passenger cabin air filter.
 13. A vehicle system, comprising a heating, ventilation, and air conditioning (HVAC) system including: a passenger cabin air filter; a blower; and a recirculation door configured to: when in a first position, allow the blower to draw air from outside of the passenger cabin through the passenger cabin air filter; and when in a second position: block airflow through the passenger cabin air filter to the blower; and allow the blower to air from within the passenger cabin to the blower; an olfaction sensor configured to measure an amount of a chemical in air upstream of the passenger cabin air filter; and a recirculation module configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount.
 14. The vehicle system of claim 13 wherein the chemical is volatile organic compounds (VOCs).
 15. The vehicle system of claim 13 wherein the chemical is particulate matter.
 16. The vehicle system of claim 13 wherein the chemical is carbon monoxide.
 17. The vehicle system of claim 13 wherein the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than the predetermined amount without receiving user input indicative of a request to actuate the recirculation door to the second position.
 18. The vehicle system of claim 13 wherein the recirculation module is further configured to actuate the recirculation door to the second position in response to receipt of user input indicative of a request to actuate the recirculation door to the second position.
 19. The vehicle system of claim 13 wherein the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount during operation of the HVAC system in a heating mode.
 20. The vehicle system of claim 13 wherein the recirculation module is configured to actuate the recirculation door to the second position when the amount of the chemical in the air upstream of the passenger cabin air filter is greater than a predetermined amount during operation of the HVAC system in a cooling mode. 